AbstractWe studied a population of paraplegic patients in order to give prominence to a possible relationship between the topography of their spinal lesion and the occurrence of special articular diseases (P.O.A.).According to the motor and sensory state of their spinal cord, we first tried to obtain a classification of these lesions (the usual one schematically separates ‘flaccid’ and ‘rigid’ paraplegics).We mainly put the emphasis on this clustering step of the study:— choice and meaning of the data and their coding;— explanation and justification of the method used: thesimilarity aggregation;— interpretation of results a